U.S. patent application number 09/742187 was filed with the patent office on 2001-07-05 for fastener driving tools having improved drive mode change devices.
Invention is credited to Kakuda, Nobuyuki, Mukoyama, Kenji.
Application Number | 20010006183 09/742187 |
Document ID | / |
Family ID | 26581935 |
Filed Date | 2001-07-05 |
United States Patent
Application |
20010006183 |
Kind Code |
A1 |
Mukoyama, Kenji ; et
al. |
July 5, 2001 |
Fastener driving tools having improved drive mode change
devices
Abstract
A fastener driving tool includes a fastener drive mechanism and
a trigger that is movable from an OFF position to an ON position
for actuating the fastener drive mechanism. A mode change device is
operable to selectively change a tool mode among a first drive
mode, a second drive mode and a drive inhibit mode for the fastener
drive mechanism. The mode change device includes an operation
member that is operable by an operator. The operation member has a
plurality of operational positions that correspond to the
changeable modes.
Inventors: |
Mukoyama, Kenji; (Anjo-shi,
JP) ; Kakuda, Nobuyuki; (Anjo-shi, JP) |
Correspondence
Address: |
DENNISON, MESEROLE, SCHEINER & SCHULTZ
Suite 612
1745 Jefferson Davis Highway
Arlington
VA
22202
US
|
Family ID: |
26581935 |
Appl. No.: |
09/742187 |
Filed: |
December 22, 2000 |
Current U.S.
Class: |
227/8 ;
227/130 |
Current CPC
Class: |
B25C 1/008 20130101 |
Class at
Publication: |
227/8 ;
227/130 |
International
Class: |
B25C 001/04 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 24, 1999 |
JP |
11-367864 |
Dec 24, 1999 |
JP |
11-367865 |
Claims
1. A fastener driving tool comprising: a fastener drive mechanism;
a trigger movable from an OFF position to an ON position for
actuating the fastener drive mechanism; and a mode change device
operable to selectively change a tool mode among a first drive
mode, a second drive mode and a drive inhibit mode for the fastener
drive mechanism; the mode change device including an operation
member that is operable by an operator, the operation member having
a plurality of operational positions that correspond to the
changeable modes.
2. A fastener driving tool as in claim 1, wherein the operation
member comprises a single member.
3. A fastener driving tool as in claim 1, further including a
control member that cooperates with the trigger for controlling the
actuation of the fastener drive mechanism, the control member being
movable between a first position and a second position, and
wherein: the first drive mode enables the actuation of the fastener
drive mechanism when the trigger and the control member are moved
in either a first sequence, in which the trigger is moved from the
OFF position to the ON position after the control member has moved
from the second position to the first position, or a second
sequence, in which the control member is moved from the first
position to the second position after the trigger has moved from
the OFF position to the ON position; and the second drive mode
enables the actuation of the fastener drive mechanism only when the
trigger and the control member are moved in either one of the first
and second sequences.
4. A fastener driving tool as in claim 3, wherein the second drive
mode enables the actuation of the fastener drive mechanism only
when the trigger and the control member are moved in the first
sequence.
5. A fastener driving tool as in claim 1, wherein the trigger
pivots about a first axis between the ON position and the OFF
position, and the mode change device is operable to change the
position of the first axis in response to change in the tool
mode.
6. A fastener driving tool as in claim 5, wherein the mode change
device includes a support shaft that is rotatably supported by a
tool body about a second axis, the support shaft having a shaft
portion that has the first axis, and the first axis and the second
axis being displaced from each other.
7. A fastener driving tool as in claim 1, wherein the trigger is
prevented from moving from the OFF position to the ON position when
the tool is in the drive inhibit mode.
8. A fastener driving tool as in claim 3, wherein the control
member comprises a contact arm that can move from the second
position to the first position upon contact with a workpiece into
which fasteners are to be driven.
9. A fastener driving tool as in claim 8, wherein the contact arm
comprises an operation portion that cooperates with the trigger for
actuation of the fastener drive mechanism, and the mode change
device is operable to shift the operation portion in a direction
substantially vertically relative to the moving direction of
operation portion when the contact arm moves between the first
position and the second position.
10. A fastener driving tool as in claim 8 further including an
idler that can pivot about a pivotal axis relative to the trigger
and serves to cooperate with the contact arm, so that the fastener
drive mechanism is actuated by the trigger and the contact arm by
means of the idler, and the mode change device is operable to shift
the position of the pivotal axis of the idler.
11. A fastener driving tool as in claim 8 further including an
idler that can pivot about a pivotal axis relative to the trigger
and serves to cooperate with the contact arm, so that the fastener
drive mechanism is actuated by the trigger and the contact arm by
means of the idler, and the mode change device is operable to
change the position of one end of the idler opposite to the pivotal
axis.
12. A fastener driving tool as in claim 8 further including a
trigger valve that is operable by the trigger and the contact arm
in the first and second drive modes for actuation of the fastener
drive mechanism.
13. A nail gun comprising: a nail drive mechanism; a trigger
movable from an OFF position to an ON position for actuating the
nail drive mechanism; a mode change device operable to selectively
change a tool mode among a first drive mode, a second drive mode
and a drive inhibit mode for the nail drive mechanism; a contact
arm serving to cooperate with the trigger for controlling the
actuation of the nail drive mechanism, the contact arm being
movable between a first position and a second position; the first
drive mode enabling the actuation of the nail drive mechanism when
the trigger and the control member are moved in either a first
sequence, in which the trigger is moved from the OFF position to
the ON position after the contact arm has moved from the second
position to the first position, and a second sequence, in which the
contact arm is moved from the first position to the second position
after the trigger has moved from the OFF position to the ON
position; the second drive mode enabling the actuation of the nail
drive mechanism only when the trigger and the control member are
moved in the first sequence; and the mode change device including
an operation member that is operable by an operator, the operation
member having a plurality of operational positions that correspond
to the changeable modes.
14. A fastener driving tool comprising: a fastener drive mechanism;
a trigger pivotable about a first axis from an OFF position to an
ON position for actuating the fastener drive mechanism; and a mode
change device operable to selectively change a tool mode between a
first mode for inhibiting the actuation of the fastener drive
mechanism, and a second mode for permitting the actuation of the
fastener drive mechanism; the mode change device being operable to
change the position of the first axis in response to change between
the first mode and the second mode.
15. A fastener driving tool as in claim 14, wherein the mode change
device includes a support shaft that is rotatably supported by a
tool body about a second axis, the support shaft including a shaft
portion that has the first axis, and the first axis and the second
axis being displaced from each other.
16. A fastener driving tool as in claim 14, wherein the trigger is
prevented from moving from the OFF position to the ON position when
in the first mode.
17. A fastener driving tool as in claim 16 further including a
stopper that is positioned to oppose to the trigger when in the
drive inhibit mode, so that the stopper can prevent the trigger
from moving from the OFF position to the ON position.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to fastener driving tools such
as pneumatic nail guns, power screwdrivers and staplers, and in
particular to fastener driving tools having drive mode change
devices.
[0003] 2. Description of the Related Art
[0004] Known pneumatic nail guns have a drive mechanism that is
disposed within a body and is driven by a compressed air. The drive
mechanism is connected to a driver and is actuated by the operation
of a trigger, so that the driver can reciprocally move to drive
nails one after another out of a driver guide that extends from the
body.
[0005] In order to prevent the nails from being accidentally
driven, a contact arm is mounted on the body so as to extend
downward from the lower end of the driver guide. When the contact
arm has pressed against a workpiece, the contact arm slides upward
relative to the driver guide to permit the trigger to actuate the
drive mechanism. Thus, the driving operation of the nails can be
performed only when the contact arm has moved upward.
[0006] Japanese Laid-Open Patent Publication No. 10-264052 teaches
a pneumatic nail gun that includes a drive mode change device, so
that the nail gun can operate in a first drive mode and a second
drive mode. In the first drive mode, the drive mechanism can be
actuated according to either a first sequence, in which the trigger
is operated after the contact arm has moved upward, or a second
sequence, in which the contact arm is moved upward after the
trigger has been operated. In the second drive mode, the drive
mechanism can be actuated according to only the first sequence.
Therefore, a nail-on-nail driving operation can be reliably
prevent.
[0007] The nail gun of this publication also includes a trigger
lock mechanism that can prevent the nails from being accidentally
driven during transportation or like occasions. Thus, the trigger
lock mechanism can prevent a trigger from moving from an OFF
position to an ON position, so that a nail drive mechanism will not
be actuated even if a contact arm has been accidentally moved by
contacting the other parts or objects during the transportation.
Thus, the trigger lock mechanism serves to provide a drive inhibit
mode.
[0008] However, the drive mode change device and the trigger lock
mechanism are operated by different operation members from each
other. Therefore, the operation for changing the drive mode between
the first or second drive mode and the drive inhibit mode is very
troublesome.
SUMMARY OF THE INVENTION
[0009] It is, accordingly, one object of the present invention to
teach improved fastener driving tools. Preferably, such fastener
driving tools can simplify the operation for changing the drive
mode.
[0010] In one aspect of the present teachings, fastener driving
tools may have a mode change device, which device enables a first
drive mode, a second drive mode and a drive inhibit mode for a
fastener drive mechanism. Preferably, the mode change device
includes an operation member that is operable by an operator. The
operation member may have a plurality of operational positions that
correspond to the changeable modes. Preferably, the operation
member is a single member.
[0011] Therefore, the operator is not required to operate different
mode change devices in response to change in the mode. In addition,
the fastener driving tool may have a simile construction.
[0012] In a representative embodiment, the drive inhibit mode can
be realized, for example, by preventing the trigger from moving
from an OFF position to an ON position. Thus, this mode may provide
a trigger lock function.
[0013] In the first drive mode, the fastener drive mechanism may be
actuated when the trigger and a control member, which may be a
contact arm, have been moved for actuating the fastener drive
mechanism in either a first sequence or a second sequence.
According to the first sequence, the trigger is moved from an OFF
position to an ON position after the control member has moved from
the second position to the first position. According to the second
sequence, the trigger is moved from the first position to the
second position after the trigger has moved from the OFF position
to the ON position.
[0014] In the second drive mode, the fastener drive mechanism can
be actuated only when the trigger and the control member are moved
according to the first sequence.
[0015] In a preferred example, the operation member of the mode
change device may be a support shaft that pivotally supports the
trigger. Preferably, the support shaft may be rotatably supported
by a tool body and may have a shaft portion, on which the trigger
is pivotally supported. The support shaft may rotate relative to
the body about a first axis, and the shaft portion may have a
second axis that is displaced from the first axis. Therefore, the
position of the first axis may change as the support shaft rotates,
so that the path of the pivotal movement of the trigger changes in
response to the rotational position of the support shaft. As a
result, the operational relationship between the trigger and the
control member or other parts of the tool that cooperate with the
trigger may change, so that the different drive modes can be
attained. This arrangement is advantageous, because the operation
member serves as a support for the trigger and also serves as a
part of the mode change device. Thus, a lock pin or like members
for exclusively providing a trigger lock function as in the known
tools are not required. Therefore, the construction of the tool
about the trigger may be simplified.
[0016] In order to change the mode, the mode change device may
change the position of a contact arm or an idler that may be
mounted on the trigger. Thus, the mode can be changed by changing
the positional relationship among the trigger and the other parts
that cooperate with the trigger for actuating the fastener drive
mechanism.
[0017] Other objects, features and advantages of the present
invention will be readily understood after reading the following
detailed description together with the accompanying drawings and
the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a right side view of a representative pneumatic
nail gun having an improved mode change device;
[0019] FIG. 2 is a sectional view of a trigger and the mode change
device of the representative nail gun;
[0020] FIG. 3 is a sectional view taken along line (3)-(3) in FIG.
2;
[0021] FIG. 4 is a sectional view illustrating the operation of the
trigger and a contact arm when the mode change device is set to an
unlimited drive mode, while the contact arm is in a lowermost
position and the trigger is in an OFF position;
[0022] FIG. 5 is a view similar to FIG. 4, but instead,
illustrating the operation when the contact arm has raised to an
uppermost position;
[0023] FIG. 6 is a view similar to FIG. 5, but instead,
illustrating the operation when the trigger has shifted to an ON
position;
[0024] FIG. 7 is a view similar to FIG. 4, but instead,
illustrating the operation when the trigger has shifted to an ON
position, while the contact arm is held in the lowermost
position;
[0025] FIG. 8 is a view similar to FIG. 7, but instead,
illustrating the operation when the contact arm has raised to the
uppermost position;
[0026] FIG. 9 is a sectional view illustrating the operation of the
trigger and a contact arm when the mode change device is set to a
limited drive mode, while the trigger is in a lowermost position
and the trigger is in an OFF position;
[0027] FIG. 10 is a view similar to FIG. 9, but instead,
illustrating the operation when the contact arm has raised to the
uppermost position;
[0028] FIG. 11 is a view similar to FIG. 10, but instead,
illustrating the operation when the trigger has shifted to the ON
position;
[0029] FIG. 12 is a view similar to FIG. 9, but instead,
illustrating the operation when the trigger has shifted to an ON
position, while the contact arm is held in the lowermost
position;
[0030] FIG. 13 is a view similar to FIG. 12, but instead,
illustrating the operation when the contact arm has raised to the
uppermost position;
[0031] FIG. 14 is a sectional view illustrating the operation of
the trigger and a contact arm when the operation mode change device
is set to a drive inhibit mode, while the trigger is in the
lowermost position and the trigger is in the OFF position; and
[0032] FIG. 15 is a view similar to FIG. 14, but instead,
illustrating the operation when the contact arm has raised to the
uppermost position.
DETAILED DESCRIPTION OF THE INVENTION
[0033] Fastener driving tools may have a body that has a fastener
drive mechanism. A trigger may move from an OFF position to an ON
position for actuating the fastener drive mechanism. A mode change
device may operate to selectively change a tool mode among a first
drive mode and a second drive mode and a drive inhibit mode for the
fastener drive mechanism. The mode change device may include an
operation member that is operable by an operator. The operation
member may have a plurality of operational positions that
correspond to the changeable drive modes. As a result, the tool can
be changed to either one of the first drive mode, the second drive
mode and the drive inhibit mode by operating the operation member.
Therefore, the mode change operation can be easily and rapidly
performed.
[0034] In a representative embodiment, the trigger cooperates with
a contact arm for actuation of the fastener drive mechanism The
contact arm may move between a first position and a second
position. Preferably, the contact arm may be moved from the first
position to the second position when the contact arm is pressed
against a workpiece.
[0035] Preferably, the first drive mode may enable the actuation of
the fastener drive mechanism when the trigger and the contact arm
are moved in either a first sequence or a second sequence.
According to the first sequence, the trigger is moved from the OFF
position to the ON position after the contact arm has moved from
the second position to the first position. According to the second
sequence, the contact arm is moved from the first position to the
second position after the trigger has moved from the OFF position
to the ON position;
[0036] The second drive mode may enable the actuation of the
fastener drive mechanism only when the trigger and the control
member are moved in the first sequence.
[0037] In a representative embodiment, the trigger may pivot about
a first axis between the ON position and the OFF position. The mode
change device may be operable to change the position of the first
axis in response to change in the tool mode and may include a
support shaft that is rotatably supported by a tool body about a
second axis. The support shaft may have a shaft portion that has
the first axis. Preferably, the first axis and the second axis are
displaced from each other.
[0038] Preferably, a stopper may be positioned to oppose to the
trigger when the tool is in the drive inhibit mode, so that the
trigger is prevented from moving from the OFF position to the ON
position. Therefore, a trigger lock function can be attained
without a lock pin as in the known tools.
[0039] In an alternative embodiment, the mode change device is
operable to shift an operation portion of the contact arm in a
direction substantially vertically relative to the moving direction
of the operation portion when the contact arm moves between the
first position and the second position.
[0040] In another alternative embodiment, the mode change device is
operable to shift a pivotal axis of an idler that cooperates with
the trigger or is operable to change the position of one end of the
idler opposite to the pivotal axis.
[0041] Each of the additional features and method steps disclosed
above and below may be utilized separately or in conjunction with
other features and method steps to provide improved fastener
driving tools and methods for designing and using such fastener
driving tools. Representative examples of the present invention,
which examples utilize many of these additional features and method
steps in conjunction, will now be described in detail with
reference to the attached drawings. This detailed description is
merely intended to teach a person of skill in the art further
details for practicing preferred aspects of the present teachings
and is not intended to limit the scope of the invention. Only the
claims define the scope of the claimed invention. Therefore,
combinations of features and steps disclosed in the following
detail description may not be necessary to practice the invention
in the broadest sense, and are instead taught merely to
particularly describe representative examples of the invention.
Moreover, various features of the representative examples may be
combined in ways that are not specifically enumerated in order to
provide additional useful embodiments of the present teachings.
[0042] A representative embodiment of a fastener driving tool will
now be described with reference to FIGS. 1 to 15.
[0043] FIG. 1 illustrates a side view of a representative pneumatic
nail gun 1, which nail gun may generally comprise a body 2 and a
handle 3 that extends rearward from the body 2. A nose 4 may be
disposed at the lower end of the body 2 and may include a driver
guide 6. A driver D may have a lower end that reciprocally moves
within the driver guide 6 so as to drive the nails out of the lower
open end of the driver guide 6.
[0044] A magazine 5 may store a plurality of nails that are joined
in series with each other. The magazine 5 may be connected between
the nose 4 and the rear end of the handle 3 and may include a nail
feeding mechanism (not show) for feeding the nails one after
another into the driver guide 6.
[0045] A pneumatic drive mechanism P may be disposed within the
body 2 and may include a piston S that can reciprocally move within
the body 2. The piston S may be connected to the driver D.
[0046] A contact arm 7 may be mounted on the driver guide 6, so
that the contact arm 7 can vertically slide along the driver guide
6. The contact arm 7 may include a contact portion 7a, and
extension 7b and an operation portion 7c. The extension 7b may
extend upward from the contact portion 7a along the driver guide 6.
The operation portion 7c may be connected to the upper end of the
extension 7b. As shown in FIG. 4, an upper part (right side part as
viewed in FIG. 4) of the operation portion 7c may be vertically
(horizontally as viewed in FIG. 4) and slidably supported by a
support bracket 9 that is mounted on the body 2, so that the upper
end of the operation portion 7c may extend adjacent to a trigger
valve 40. As shown in FIG. 1, the trigger valve 40 may be disposed
on the rear side of the body 2 in the vicinity of the handle 3.
[0047] A driving depth adjusting device 8 may be interposed between
the operation portion 7c and the extension 7b and may be operable
to change the position of the operation portion 7c relative to the
extension 7b, so that the driving depth of nails into workpieces
(not shown) can be changed.
[0048] A compression spring (not shown) may downwardly bias the
contact arm 7, so that the contact arm 7 can be normally held in a
lowermost position, in which the lower end of the contact portion
7a extends downward from the lower end of the driver guide 6 as
shown in FIG. 1. Therefore, the contact arm 7 can move upward from
the lowermost position by a distance that corresponds to the
extending distance of the contact portion 7a from the lower end of
the driver guide 6.
[0049] When the contact portion 7a of the contact arm 7 is pressed
against a workpiece (not shown) by downwardly pressing the nail gun
1 against the workpiece, the contact arm 7a may move upward against
the biasing force of the spring, so that the operation portion 7c
moves from an inoperative position to an operative position toward
the trigger valve 40. However, in this representative embodiment,
the trigger valve 40 may not open even if the operation portion 7c
has moved to the operative position. In order to open the trigger
valve 40, an operator pulls a trigger 30 so as to move the trigger
30 from an OFF position to an ON position.
[0050] As shown in FIGS. 2 and 3, the trigger 30 may be vertically
pivotally mounted on a support shaft 35. The support shaft 35 may
be supported between a pair of bifurcated support walls 2a and 2b
that are formed integrally with the body 2 adjacent to the trigger
valve 40. As shown in FIG. 3, the support shaft 35 may have a short
large-diameter portion 35a and a long small-diameter portion 35b.
Preferably, a central axis C1 of the large-diameter portion 35a may
be displaced by a distance L from a central axis C2 of the
small-diameter portion 35b.
[0051] The support shaft 35 may be rotatably supported between the
support walls 2a and 2b. More specifically, the large-diameter
portion 35a may be rotatably received within a support hole 2c
formed in the support wall 2a. One end of the small-diameter
portion 35b opposite to the large-diameter portion 35a may be
supported by a support cap 36, such that the small-diameter portion
35b can rotate relative to the support cap 36 but cannot move in
the axial direction. The support cap 36 also may be rotatably
mounted on the support wall 2b.
[0052] The trigger 30 may be rotatably supported by the
small-diameter portion 35b, so that the trigger 30 can pivot about
the central axis C2.
[0053] A knob 37 may be formed integrally with one end of the
large-diameter portion 35a opposite to the small-diameter portion
35b and may be rotated by an operator. A ball 38, preferably made
of steel, may be disposed within a ball receiving hole 43 that is
formed in the knob 37 in a position opposite to the outer surface
of the wall portion 2a. A compression spring 39 may also be
disposed within the ball receiving hole 43 and may serve to bias
the ball 38 toward the wall portion 2a. First to third
hemispherical recesses 2d, 2e and 2f may be formed in the outer
surface of the wall portion 2a and may be positioned on a circle
about the central axis C1, which circle has a radius that is equal
to the distance between the ball 38 and the central axis C1.
Preferably, the first to third recesses 2d, 2e and 2f are displaced
from each other by an angle of 90.degree.. Therefore, as the knob
37 rotates, the ball 38 can engage either one of the first to third
recesses 2d, 2e and 2f. As a result, the rotational position of the
support shaft 35 can be held in three different positions about the
central axis C1.
[0054] As the support shaft 35 rotates, the small-diameter portion
35b may rotate about its own axis or the central axis C1, while it
moves along a circle having a radius that is equal to the distance
L.
[0055] When the ball 38 engages the first recess 2d, the
small-diameter portion 35b may be positioned in an uppermost
position 35bR as viewed in FIG. 2 (leftmost position as viewed in
FIG. 1) above the central axis C1 of the large-diameter portion
35a. With the support shaft 35 positioned in this rotational
position, the nail gun 1 can operate in an unlimited drive
mode.
[0056] When the operator rotates the support shaft 35 from the
uppermost position 35bR by and angle of 180.degree.in a
counterclockwise direction as viewed in FIG. 2, the ball 38 may
engage the second recess 2e, so that the small-diameter portion 35b
may be positioned in a lowermost position 35bS as viewed in FIG. 2
(rightmost position as viewed in FIG. 1) below the central axis C1
of the large-diameter portion 35a. With the support shaft 35
positioned in this rotational position, the nail gun can be
operated in a limited drive mode.
[0057] When the operator further rotates the support shaft 35 from
the rightmost position 35bS by and angle of 90.degree. in a
counterclockwise direction as viewed in FIG. 2, the ball 38 may
engage the third recess 2e, so that the small-diameter portion 35b
may be positioned in a intermediate position 35bT at the same level
as central axis C1 of the large-diameter portion 35a and may be
displaced rightward as viewed in FIG. 2 (upward as viewed in FIG.
1) from the central axis C1 toward the trigger valve 40. With the
support shaft 35 set in this rotational position, an operator
cannot perform a nail driving operation. Thus, the nail gun 1 is
set to a drive inhibit mode.
[0058] As shown in FIG. 2, a stopper protrusion 30a may be formed
on the upper end (left end as viewed in FIG. 1) of the trigger 30
and may extend rightward (upward as viewed in FIG. 1) from the
trigger 30. On the other hand, a stopper wall 2g may be formed on a
part of the body 2 that opposes to the stopper protrusion 30a.
Preferably, the stopper wall 2g may be formed on a base portion of
the bifurcated pair of the wall portions 2a and 2b.
[0059] When the nail gun 1 is set to the drive inhibit mode, the
stopper protrusion 30a may be positioned adjacent to and below the
stopper wall 2g as shown in FIG. 14. Therefore, the stopper wall 2g
may prevent the trigger 30 from moving from the OFF position to the
ON position.
[0060] On the other hand, when the nail gun 1 is set to the
unlimited drive mode, the stopper protrusion 30a may be positioned
above the stopper wall 2g as shown in FIG. 4. Therefore, the
stopper wall 2g may not interfere with the shifting movement of the
trigger 30 from the OFF position to the ON position. When the nail
gun 1 is set to the limited drive mode, the stopper protrusion 30a
may be positioned below the stopper wall 2b as shown in FIG. 8 but
may be displaced leftward (downward as viewed in FIG. 1) from the
stopper wall 2b. Therefore, also in this mode, the stopper wall 2g
may not interfere with the shifting movement of the trigger 30 from
the OFF position to the ON position.
[0061] Thus, in this representative embodiment, various parameters
are chosen to enable the above different modes of the nail gun 1
including the unlimited drive mode, the limited drive mode and the
drive inhibit mode. Such parameters may include the position of the
support shaft 35, the distance L between the central axis C1 of the
large diameter portion 35a and the central axis C2 of the
small-diameter portion 35b, and the positions and the
configurations of the stopper protrusion 30a and the stopper wall
2g.
[0062] As shown in FIG. 2, an idler 31 may have one end that is
pivotally connected to the right and lower side (upper and right
side as viewed in FIG. 1) of the trigger 30 by means of a pivot pin
31a. The other end of the idler 31 may extend to a position
adjacent to the support shaft 35.
[0063] As shown in FIG. 1, a trigger valve 40 may be mounted within
the body 2 and may be positioned adjacent to the stopper wall 2g
(see FIG. 4), so that a valve stem 41 of the trigger valve 40
opposes to substantially the central portion of the idler 31. The
trigger valve 40 may open when the valve stem 41 has retracted into
the body of the trigger valve 40 by a predetermined distance. Then,
a compressed air may be supplied to an upper air chamber (not
shown) above the piston S of the pneumatic drive mechanism P. As a
result, the piston S may move downward with the driver D, so that
the nail can be driven out of the driver guide 6.
[0064] A compression spring 42 may be interposed between the idler
31 and the trigger valve 40, so that the idler 31 may be biased in
a direction away from the valve stem 41. Therefore, the trigger 30
also may be biased by means of the idler 31 in a clockwise
direction as viewed in FIG. 4. The trigger 30 may include a stopper
portion 30b and may normally contact the support bracket 9 by the
biasing force of the compression spring 42, so that the trigger 30
can be held in the OFF position against the biasing force. FIGS. 1,
4, 5, 9, 10, 14 and 15 show the trigger 30 in the OFF position.
[0065] The operation of the representative nail gun 1, in
particular the operation of the trigger valve 40, in the above
unlimited drive mode, the limited drive mode and the drive inhibit
mode will now be explained in connection with the operation of the
contact arm 7 and the trigger 30.
[0066] FIG. 4 shows the nail gun 1 in the unlimited drive mode, in
which the small-diameter portion 35b of the support shaft 35 is in
the position 35bR above the central axis C1 of the large-diameter
portion 35a, while the contact arm 7 is in the lowermost position
and the trigger 30 is in the OFF position.
[0067] When the contact arm 7 moves upward (rightward as viewed in
FIG. 4), the operation portion 7c pushes the upper portion of the
idler 31, so that the idler 31 pivots toward the trigger valve 40
against the biasing force of the compression spring 42 as shown in
FIG. 5. As a result, the valve stem 41 may retract by a little
distance into the valve body of the trigger valve 40. However, this
retracting distance is insufficient to open the trigger valve 40.
Therefore, the trigger valve 40 may still be held in a close
position.
[0068] Then, the operator pulls the trigger 30 to pivot the trigger
30 in a counterclockwise direction as viewed in FIG. 5, so the
trigger 30 moves from the OFF position to the ON position. As a
result, the pivot pin 31a of the idler 31 may move toward the
trigger valve 40, so that the entire idler 31 moves toward the
trigger valve 40. Therefore, the valve stem 41 further retracts to
open the trigger valve 40 as shown in FIG. 6, so that the nail can
be driven into a workpiece (not shown).
[0069] In the state of FIG. 4, the stopper protrusion 30a of the
trigger 30 is positioned above the stopper wall 2b of the body 2.
Therefore, as shown in FIG. 7, the trigger 30 can be moved from the
OFF position to the ON position without being interfered with the
stopper wall 2b, even before the upward movement of the contact arm
7. In this case, the pivot pin 31a of the idler 31 may move toward
the trigger valve 40. However, this movement of the idler 31 may
not cause substantial retraction of the valve stem 41 into the body
of the trigger valve 40. Therefore, the trigger valve 40 may not
open.
[0070] In order to open the trigger valve 40, the contact arm 7 may
be moved to the uppermost position, so that the upper portion of
the idler 31 may be pushed toward the trigger valve 40 against the
biasing force of the compression spring 42 as shown in FIG. 8. As a
result, the valve stem 41 may retract by a sufficient amount to
open the trigger valve 40.
[0071] Therefore, in the unlimited drive mode, the driving
operation of the nails can be performed according to either a first
sequence, in which the trigger 30 is operated after the upward
movement of the contact arm 7, or a second sequence, in which the
contact arm 7 is moved upward after the operation of the trigger
30.
[0072] FIG. 9 shows the nail gun 1 in the limited drive mode, in
which the small-diameter portion 35b of the support shaft 35 is in
the position 35bS below the central axis C1 of the large-diameter
portion 35a and is displaced leftward (downward as viewed in FIG.
1) from the stopper wall 2b. Thus, in this mode, the pivotal axis
of the trigger 30 is disposed at a level lower than that in the
unlimited drive mode by a distance of 2L. Therefore, the idler 31
also is disposed at a lever lower than that in the unlimited drive
mode by a distance of 2L. Also, in FIG. 9, the contact arm 7 is in
the lowermost position and the trigger 30 is in the OFF
position.
[0073] When the contact arm 7 moves upward (rightward as viewed in
FIG. 9), the operation portion 7c pushes the upper portion of the
idler 31, so that the idler 31 pivots toward the trigger valve 40
against the biasing force of the compression spring 42 as shown in
FIG. 10. As a result, the valve stem 41 may retract by a little
distance into the body of the trigger valve 40. However, the
retracting distance is insufficient to open the trigger valve 40.
Therefore, the trigger valve 40 may still be held in a close
position.
[0074] Then, the operator pulls the trigger 30 to pivot the trigger
30 in a counterclockwise direction as viewed in FIG. 10, so the
trigger 30 moves from the OFF position to the ON position. As a
result, the pivot pin 31a of the idler 31 may move toward the
trigger valve 40, so that the entire idler 31 moves toward the
trigger valve 40. Therefore, the valve stem 41 further retracts to
open the trigger valve 40 as shown in FIG. 11. As a result, the
nail can be driven into a workpiece.
[0075] In the state of FIG. 9, the stopper protrusion 30a of the
trigger 30 is displaced leftward (downward as viewed in FIG. 1)
from the stopper wall 2b. Therefore, as shown in FIG. 12, the
trigger 30 can move from the OFF position to the ON position
without being interfered with the stopper wall 2b, even before the
upward movement of the contact arm 7. Although the pivot pin 31a of
the idler 31 may move toward the trigger valve 40, this movement of
the idler 31 may not cause substantial retraction of the valve stem
41 into the valve body of the trigger valve 40. Therefore, the
trigger valve 40 may not open.
[0076] In addition, as the trigger 30 moves from the OFF position
to the ON position, the upper end of the idler 31 opposite to the
pivot pin 31a may move to a position below a moving path of the
operation portion 7c of the contact arm 7 as shown in FIG. 12.
Therefore, even when the contact arm 7 has moved upward to extend
the operation portion 7c toward the trigger valve 40, the operation
portion 7c may not contact the idler 31, but instead, may pass over
the upper end of the operation portion 7c as shown in FIG. 13.
Therefore, the idler 31 cannot move to retract the valve stem 41
into the trigger valve 40.
[0077] Therefore, in the limited drive mode, the driving operation
of the nails cannot be performed according to the second sequence,
in which the contact arm 7 is moved upward after the trigger 30 has
been operated. Thus, the driving operation can be made according to
only the first sequence.
[0078] FIG. 14 shows the nail gun 1 in the drive inhibit mode, in
which the small-diameter portion 35 of the support shaft 35 is in
the position 35bT that is an intermediate position between the
positions 35bR and 35bS in the vertical direction as viewed in FIG.
2 and is displaced from the positions 35bR and 35bS by the distance
L toward the trigger valve 40. In this mode, the stopper protrusion
30a of the trigger 30 may be positioned adjacent to and below the
stopper wall 2g. Therefore, the trigger 30 is prevented by the
stopper wall 2g from moving from the OFF position to the ON
position.
[0079] When the contact arm 7 has moved upward as shown in FIG. 15,
the operation portion 7c may push the idler 31 to retract the valve
stem 41 by a small distance. However, this retracting distance is
not sufficient to open the trigger valve 40. As a result, the
driving operation of the nail may not be performed.
[0080] As described above, according to the representative nail gun
1, the operation mode of the nail gun 1 can be selectively changed
among the unlimited drive mode, the limited drive mode and the
drive inhibit mode by rotating the support shaft 35 by means of the
knob 37. Because the knob 37 or the support shaft 35 is a single
member, the mode changing operation can be easily and rapidly
performed. Therefore, the representative nail gun 1 has an improved
operability.
[0081] Also, as described above, in the unlimited drive mode, the
driving operation can be performed according to either the first
sequence or the second sequence. On the other hand, in the limited
drive mode, the driving operation can be performed according to
only the first sequence. Thus, in the limited mode, the driving
operation can be performed only when the trigger 30 is operated
after the contact arm 7 has moved to the uppermost position.
Therefore, this mode serves to prevent a nail driving operation, in
which the nails are driven by repeatedly reciprocating the contact
arm 7, while the operator holds the trigger 30 in the ON position.
As a result, an accidental nail-on-nail driving operation can be
reliably prevented.
[0082] In the drive inhibit mode, the trigger 30 may be prevented
from moving from the ON position to the OFF position. In addition,
the nails may not be driven even if the contact arm has moved to
the uppermost position. Therefore, an accidental driving operation
of the nails can be reliably prevented. In particular, with the
nail gun 1 set to this mode, the nails will not be driven even if
the contact arm has accidentally moved to the uppermost position by
contacting the other parts or objects during transportation.
Therefore, this representative embodiment is advantageous also in
this respect.
[0083] In addition, because the drive inhibit mode can be attained
by rotating the support shaft 35 that supports the trigger 30, no
additional lock pin is required to fix the trigger 30 in the OFF
position. Therefore, a trigger lock function can be realized with a
simple construction about the trigger 30.
[0084] Although in the above representative embodiment, the support
shaft 35 is shifted relative to the operation portion 7c of the
contact arm 7 and the idler 30 in order to change the operation
mode, the operation portion 7c or the position of the pivot pin 31a
may be shifted instead of the support shaft 35 to change the
operation mode.
[0085] For example, a mode change device (not show) may shift the
operation portion 7c among three different levels (not shown) in
the vertical direction as viewed in FIG. 4. The operation portion
7c at an upper level may be positioned above the upper end of the
idler 31. In this position, the operation portion 7c will not
contact the upper portion of the idler 31 even when the contact arm
7 has moved to the uppermost position (rightmost position as viewed
in FIG. 4). Therefore, the trigger valve 40 will not open even if
the trigger 30 has moved from the OFF position to the ON position.
Thus, the drive inhibit mode can be realized. The operation portion
7c at an intermediate level may be positioned adjacent to the upper
end of the idler 31, so that the idler 31 can be pushed by the
operation portion 7c only before the trigger 30 has moved from the
OFF position to the ON position. As a result, the limited drive
mode can be realized. The operation portion 7c at a lower level may
push the idler 31 irrespective of the position of the trigger 30.
Therefore, the unlimited drive mode can be realized.
[0086] In the same manner, a mode change device (not shown) may
shift the pivot pin 31a of the idler 31 among three different
levels (not shown) in the vertical direction relative to the
trigger 30, so that the unlimited drive mode, the limited drive
mode and the drive inhibit mode can be realized. Alternatively, the
idler 31 may be modified such that the idler 31 can extend to
change the upper end position of the idler 31 at three different
positions.
[0087] Although the above representative embodiment has been
described in connection with the pneumatic nail gun, the present
invention can also be applied to the other kind of fastener driving
tools such as staplers and screwdrivers.
* * * * *